[kernel/f16] Fix oopses on removal of external disks

[Chuck Ebbert]

commit c5c0d51eb59d13dccd975525ab2a511a8704b004
Author: Chuck Ebbert <cebbert at redhat.com>
Date:   Mon Oct 3 23:01:13 2011 -0400

    Fix oopses on removal of external disks

 777eb1bf15b8532c396821774bf6451e563438f5.patch |   71 ++++++++++++++++++++++++
 kernel.spec                                    |    7 ++
 2 files changed, 78 insertions(+), 0 deletions(-)
---
diff --git a/777eb1bf15b8532c396821774bf6451e563438f5.patch b/777eb1bf15b8532c396821774bf6451e563438f5.patch
new file mode 100644
index 0000000..7826375
--- /dev/null
+++ b/777eb1bf15b8532c396821774bf6451e563438f5.patch
@@ -0,0 +1,71 @@
+From 777eb1bf15b8532c396821774bf6451e563438f5 Mon Sep 17 00:00:00 2001
+From: Hannes Reinecke <hare at suse.de>
+Date: Wed, 28 Sep 2011 08:07:01 -0600
+Subject: [PATCH] block: Free queue resources at blk_release_queue()
+
+A kernel crash is observed when a mounted ext3/ext4 filesystem is
+physically removed. The problem is that blk_cleanup_queue() frees up
+some resources eg by calling elevator_exit(), which are not checked for
+in normal operation. So we should rather move these calls to the
+destructor function blk_release_queue() as at that point all remaining
+references are gone. However, in doing so we have to ensure that any
+externally supplied queue_lock is disconnected as the driver might free
+up the lock after the call of blk_cleanup_queue(),
+
+Signed-off-by: Hannes Reinecke <hare at suse.de>
+Signed-off-by: Jens Axboe <axboe at kernel.dk>
+---
+ block/blk-core.c  |   13 ++++++-------
+ block/blk-sysfs.c |    5 +++++
+ 2 files changed, 11 insertions(+), 7 deletions(-)
+
+diff --git a/block/blk-core.c b/block/blk-core.c
+index b2ed78a..d34433a 100644
+--- a/block/blk-core.c
++++ b/block/blk-core.c
+@@ -348,9 +348,10 @@ void blk_put_queue(struct request_queue *q)
+ EXPORT_SYMBOL(blk_put_queue);
+ 
+ /*
+- * Note: If a driver supplied the queue lock, it should not zap that lock
+- * unexpectedly as some queue cleanup components like elevator_exit() and
+- * blk_throtl_exit() need queue lock.
++ * Note: If a driver supplied the queue lock, it is disconnected
++ * by this function. The actual state of the lock doesn't matter
++ * here as the request_queue isn't accessible after this point
++ * (QUEUE_FLAG_DEAD is set) and no other requests will be queued.
+  */
+ void blk_cleanup_queue(struct request_queue *q)
+ {
+@@ -367,10 +368,8 @@ void blk_cleanup_queue(struct request_queue *q)
+ 	queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
+ 	mutex_unlock(&q->sysfs_lock);
+ 
+-	if (q->elevator)
+-		elevator_exit(q->elevator);
+-
+-	blk_throtl_exit(q);
++	if (q->queue_lock != &q->__queue_lock)
++		q->queue_lock = &q->__queue_lock;
+ 
+ 	blk_put_queue(q);
+ }
+diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
+index e681805..60fda88 100644
+--- a/block/blk-sysfs.c
++++ b/block/blk-sysfs.c
+@@ -479,6 +479,11 @@ static void blk_release_queue(struct kobject *kobj)
+ 
+ 	blk_sync_queue(q);
+ 
++	if (q->elevator)
++		elevator_exit(q->elevator);
++
++	blk_throtl_exit(q);
++
+ 	if (rl->rq_pool)
+ 		mempool_destroy(rl->rq_pool);
+ 
+-- 
+1.7.5.4
+
diff --git a/kernel.spec b/kernel.spec
index cf7aa74..6b04665 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -735,6 +735,8 @@ Patch20000: utrace.patch
 # Flattened devicetree support
 Patch21000: arm-omap-dt-compat.patch
 Patch21001: arm-smsc-support-reading-mac-address-from-device-tree.patch
+
+Patch21010: 777eb1bf15b8532c396821774bf6451e563438f5.patch
 %endif
 
 BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -1352,6 +1354,8 @@ ApplyPatch powerpc-Fix-deadlock-in-icswx-code.patch
 # utrace.
 ApplyPatch utrace.patch
 
+ApplyPatch 777eb1bf15b8532c396821774bf6451e563438f5.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -2053,6 +2057,9 @@ fi
 # and build.
 
 %changelog
+* Mon Oct 03 2011 Chuck Ebbert <cebbert at redhat.com> 3.1.0-0.rc8.git0.1
+- block: Free queue resources at blk_release_queue()
+
 * Thu Sep 29 2011 Chuck Ebbert <cebbert at redhat.com>
 - Require grubby >= 8.3-1 so initrd line gets added (rhbz #725185)